272 ANNUAL REPORT SMITHSONIAN INSTITUTION, 194 7 



giving rise to a wave of greater size than either. Likewise, the simul- 

 taneous arrival by different routes of a wave crest and a wave trough 

 may effectually cancel out both. Thus, variations in the size and in- 

 tensity of waves, particularly on the sides of the islands away from the 

 wave origin, may result from the arrival, either in or out of phase, of 



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FiGTTEE 7. — Map of the island of Hawaii, showing heights (in feet above lower low 

 water) reached by the water during the tsunami of April 1, 1946. 



two wave trains. During the tsunami of 194G several examples of the 

 formation of a large wave by the juncture of two smaller ones were 

 observed. Thus, in the Keaukaha area east of Hilo, witnesses described 

 the arrival of a wave from the north simultaneously with one from 

 the northeast, which built up a very high crest at the place of juncture. 

 At the head of Maunalua Bay, on the southeastern shore of Oahu, two 

 waves were seen to advance up channels across the wide reef, move 

 toward each other parallel with the shore, and meet, throwing water 



